Coated article having low-e coating with ir reflecting layer(s) and high index nitrided dielectric layers

ABSTRACT

A coated article includes a low emissivity (low-E) coating having at least one infrared (IR) reflecting layer of a material such as silver, gold, or the like, and a plurality of high refractive index dielectric layers of or including a nitride of Zr and Al. In certain example embodiments, the high refractive index dielectric layers of or including a nitride of Zr and Al may be amorphous or substantially amorphous so as to allow the low-E coating to better withstand optional heat treatment (HT) such as thermal tempering. In certain example embodiments, the low-E coating may be used in applications such as monolithic or insulating glass (IG) window unit, vehicle windows, of the like.

Example embodiments of this invention relate to a coated articleincluding a low emissivity (low-E) coating having at least one infrared(IR) reflecting layer of a material such as silver, gold, or the like,and a plurality of high refractive index dielectric layers of orincluding a nitride of Zr and Al. In certain example embodiments, thehigh refractive index dielectric layers of or including a nitride of Zrand Al may be amorphous or substantially amorphous so as to allow thelow-E coating to better withstand optional heat treatment (HT) such asthermal tempering. In certain example embodiments, the low-E coating maybe used in applications such as monolithic or insulating glass (IG)window unit, vehicle windows, of the like.

BACKGROUND AND SUMMARY OF EXAMPLE EMBODIMENTS OF THE INVENTION

Coated articles are known in the art for use in window applications suchas insulating glass (IG) window units, vehicle windows, monolithicwindows, and/or the like.

Conventional low-E coatings are disclosed, for example and withoutlimitation, in U.S. Pat. Nos. 6,576,349, 9,212,417, 9,297,197,7,390,572, 7,153,579, and 9,403,345, the disclosures of which are herebyincorporated herein by reference.

Certain low-E coating utilize at least one transparent dielectric layerof titanium oxide (e.g., TiO₂), which has a high refractive index (n),for antireflection and/or coloration purposes. See for example U.S. Pat.Nos. 9,212,417, 9,297,197, 7,390,572, 7,153,579, and 9,403,345. Althoughhigh refractive index dielectric material TiO₂ is known and used inlow-E coatings, TiO₂ has a very low sputter-deposition rate and is notthermally stable upon heat treatment such as thermal tempering of about650C for 8 minutes, due to film crystallization (or change incrystallinity) in as-deposited or post-tempering state, which may inturn induce thermal or lattice stress on adjacent layers in the filmstack. Such stress can further cause change in physical or materialproperties of the stack and hence impact on the Ag layer, which resultsin deteriorated low E stack performance. The low sputter deposition rateof TiO₂ leads to significantly high costs associated with making low-Ecoatings including such layer(s).

Example embodiments of this invention solve these problems by providinga coated article including a low emissivity (low-E) coating having atleast one infrared (IR) reflecting layer of a material such as silver,gold, or the like, and a plurality of high refractive index dielectriclayers of or including a nitride of Zr and Al. In certain exampleembodiments, the high refractive index dielectric layers of or includinga nitride of Zr and Al may be amorphous or substantially amorphous so asto allow the low-E coating to better withstand optional heat treatment(HT) such as thermal tempering. In certain example embodiments of thisinvention, the low-E coating includes a layer sequence of glass . . .ZrAlN/ZnO/Ag/contact/ZnO/ZrAlN . . . overcoat, where the ZnO inclusivelayers may further contain Al or the like. It has been found that such asequence advantageously provides for increased sputter deposition ratesand thus lower cost, high transparency, good durability, good opticalperformance, and good thermal performance. In certain exampleembodiments, the low-E coating may be used in applications such asmonolithic or insulating glass (IG) window unit, vehicle windows, of thelike.

In an example embodiment of this invention, there is provided a coatedarticle including a coating supported by a glass substrate, the coatingcomprising: a first high index dielectric layer comprising a nitride ofZr and Al on the glass substrate, wherein the first high indexdielectric layer comprising the nitride of Zr and Al contains more Zrthan Al; a first dielectric layer comprising zinc oxide on the glasssubstrate located over and directly contacting the first high indexlayer comprising the nitride of Zr and Al; a first infrared (IR)reflecting layer on the glass substrate, located over and directlycontacting the first dielectric layer comprising zinc oxide; a firstcontact layer on the glass substrate located over and directlycontacting the first IR reflecting layer; a second dielectric layercomprising zinc oxide on the glass substrate located over and directlycontacting the first contact layer; a second high index dielectric layercomprising a nitride of Zr and Al on the glass substrate located overand directly contacting the second dielectric layer comprising zincoxide, wherein the second high index dielectric layer comprising thenitride of Zr and Al contains more Zr than Al; and another dielectriclayer on the glass substrate located over at least the first and secondhigh index dielectric layers and the first IR reflecting layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of a layer sequence of a coated articleaccording to an example embodiment of this invention.

FIG. 2 is a cross sectional view of a coated article according to anexample embodiment of this invention, including the layer sequence shownin FIG. 1.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

Referring now to the drawings in which like reference numerals indicatelike parts throughout the several views.

Coated articles herein may be used in applications such as monolithicwindows, IG window units such as residential windows, patio doors,vehicle windows, and/or any other suitable application that includessingle or multiple substrates such as glass substrates.

Example embodiments of this invention provide a coated article includinga low emissivity (low-E) coating having at least one infrared (IR)reflecting layer 5, 5′ of a material such as silver, gold, or the like,and a plurality of high refractive index dielectric layers 2, 2′, 2″ ofor including a nitride of Zr and Al. In certain example embodiments, thehigh refractive index dielectric layers 2, 2′, 2″ of or including anitride of Zr and Al may be amorphous or substantially amorphous so asto allow the low-E coating to better withstand optional heat treatment(HT) such as thermal tempering. In certain example embodiments of thisinvention, the low-E coating includes a layer sequence of glass . . .ZrAlN/ZnO/Ag/contact/ZnO/ZrAlN . . . overcoat (in variousstoichiometries), where the ZnO inclusive layers 4, 4′, 7, 7′ mayfurther contain Al or the like. In the FIG. 2 embodiment, two of theselayer sequences are provided, one for each of the IR reflecting layers.It has been found that such a sequence advantageously provides forincreased sputter deposition rates and thus lower cost, hightransparency, good durability, good optical performance, and goodthermal performance. In certain example embodiments, the low-E coatingmay be used in applications such as monolithic or insulating glass (IG)window unit, vehicle windows, of the like.

For example, high index transparent dielectric layers 2, 2′, and 2″ mayeach be of or include ZrSiN and/or ZrSiAlN (in various stoichiometries).The high index layers 2, 2′ and/or 2″ of or including ZrSiN and/orZrSiAlN may be amorphous or substantially amorphous, with the amorphousaspect helping the low-E coating to better withstand optional heattreatment (HT) such as thermal tempering. The high index layers 2, 2′and/or 2″ of or including ZrSiN and/or ZrSiAlN have a faster sputteringrate than high index material TiO₂ at like thickness, and thus lead tolower production costs. The high index layers 2, 2′ and/or 2″ of orincluding ZrSiN and/or ZrSiAlN can also be sputter-deposited in anamorphous or substantially amorphous manner, leading to improved thermalstability compared to high index material TiO₂.

The chemical representations herein where Zr is included are providedfor purposes of simplicity and understanding, and are not necessarilystoichiometric. For example, ZrSiN does not mean that equal amounts ofZr, Si and N are provided. As another example, ZrSiAlN does not meanthat equal amounts of Zr, Si, Al and N are provided. Instead, forexample and without limitation, a ZrSiN layer may include more Zr thanSi, and so forth. As another example, a ZrSiAlN layer may contain moreZr than Si, and more Zr than Al.

“Heat treatment” (HT) and like terms such as “heat treating” and “heattreated”, such as thermal tempering, heat strengthening, and/or heatbending, as used herein means heat treating the glass substrate andcoating thereon at temperature of at least 580 degrees C. for at least 5minutes. An example heat treatment is heat treating at temperature ofabout 600-650 degrees C. for at least 8 minutes.

It has been found that adding Zr to SiAlN and SiN allows widening of itsband-gap, and thus lowers considerably the optical absorption (k) whileincreasing refractive index (n). These materials have also been found tobe heat stable (e.g., the variation of refractive index n may be low dueto HT such as thermal tempering at about 650° C.). Thus, the addition ofZr to SiAlN and SiN provides for an improvement because it causes theresulting layer to have a higher refractive index and lower absorptioncoefficient. In certain example embodiments of this invention,sufficient Zr is provided in layer(s) 2, 2′, and/or 2″ of or includingZrSiN and/or ZrSiAlN so that layer(s) 2, 2′ and/or 2″ have a highrefractive index (n) of at least 2.21, more preferably of at least 2.25,even more preferably of at least 2.30 (at 550 nm).

An example metal content of a ZrSiAlN layer 2, 2′ and/or 2″ is asfollows with respect to atomic ratio: Zr:Si:Al→62.6:31.3:6.7:30.7. Inother words, Zr makes up 62.6%, Si makes up 6.7%, and Al makes up 30.7%of the metal content of the nitrided layer 2, 2′, 2″ in terms of atomic%. In certain example embodiments of this invention, metal content ofthe ZrSiN and/or ZrSiAlN dielectric layer(s) 2, 2′ and 2″ may contain:(i) from 30-80% Zr, more preferably from 35-75% Zr, even more preferablyfrom 55-70% Zr (atomic %); (ii) from 0-50% Si, more preferably from3-25% Si, even more preferably from 3-15% Si (atomic %); and (iii) from10-60% Al, more preferably from 15-50% Al, even more preferably from20-40% Al, and most preferably from 25-36% Al (atomic %). Note that Siis considered a metal herein. In certain example embodiments, layer(s)2, 2′, 2″ contain more Zr than Si, and more Zr than Al, in terms ofatomic percentage. In certain example embodiments, Zr has the highestmetal content of any metal in layer(s) 2, 2′, 2″ and/or Al has thesecond highest metal content of any metal in layer(s) 2, 2′, 2″. Incertain example embodiments, layers 2, 2′, 2″ contain at least twice asmuch Zr as Si, more preferably at least three times as much Zr as Si,even more preferably at least four times as much Zr as Si, and mostpreferably at least five times as much Zr as Si (in terms of atomic %).In certain example embodiments, layer(s)2, 2′, 2″ contain at least 1.2times as much Zr as Al, more preferably at least 1.4 times as much Zr asAl, and most preferably at least 1.7 times as much Zr as Al (in terms ofatomic %). For example, when layer 2, 2′ and/or 2″ contains 31% Al and63% Zr, it contains 2.032 times as much Zr as Al (i.e., 63/31=2.032).

The metal content of the ZrSiN and/or ZrSiAlN dielectric layer(s) 2, 2′,2″ is preferably free of, or substantially free of, Ti and/or Nb.Layer(s) 2, 2′, 2″ may contain from 0-10% of Ti, more preferably from0-5% Ti, and most preferably from 0-2% of Ti (atomic %), and/or from0-10% of Nb, more preferably from 0-5% Nb, and most preferably from 0-2%of Nb.

While oxygen is not preferred in high index ZrSiN and/or ZrSiAlNdielectric layers 2, 2′, 2″ discussed herein, it is possible that theselayers may contain a small amount of oxygen, especially in view ofcrosstalk from an adjacent zinc oxide layer also be sputter deposited.For example, high index ZrSiN and/or ZrSiAlN dielectric layers 2, 2′, 2″may contain from 0-10% oxygen more preferably from 0-5% oxygen, and mostpreferably from 0-4% oxygen (atomic %).

FIG. is a cross sectional view of a layer sequence of a coated articleaccording to an example embodiment of this invention, and FIG. 2 is across sectional view of a coated article according to an exampleembodiment of this invention including two of the layer sequences shownin FIG. 1.

Referring to FIG. 1, the coated article includes glass substrate S and alayer sequence of or including high index transparent ZrSiN and/orZrSiAlN dielectric layer 2 (or 2′), transparent dielectric layer 4 (or4′) of or including zinc oxide which may be doped with from 1-10% Al(atomic %) and which may optionally include tin, IR reflecting layer 5(or 5′) of or including silver, gold, or the like, contact layer 6 (or6′) of or including a material such as NiCr, NiCrO_(x), NiCrMoO_(x),NiCrMo, or NiTiNbO_(x), transparent dielectric layer 7 (or 7′) of orincluding zinc oxide which may be doped with from 1-10% Al (atomic %)and which may optionally include tin, and another high index transparentZrSiN and/or ZrSiAlN dielectric layer 2′ (or 2″). One or more layers maybe provided over the layer sequence described above, such as includingan overcoat 10 of or including silicon nitride, silicon oxynitride,and/or silicon oxide (e.g., Sift). One such sequence may be provided ina single silver low-E coating, whereas one or more of such sequences maybe provided in double or triple silver low-E coatings.

It has been found that a unique design in a double silver low-E coatingfor example, using a two block of sequence of glass . . . ZrAlN(or ZrAlalloy)/ZnAlO/Ag/contact/ZnAlO/ZrAlN(or ZrAl alloy) . . . overcoat,provides numerous advantages. ZrSiAlN may be used instead of ZrAlN incertain embodiments for layers 2, 2′ and/or 2″. This layer stacksequence provides for excellent substantially neutral color, hightransparency, high throughput, long queue time and thus good durability,and low cost. Such coatings may be used to achieve excellent optical andthermal performance of low-E IG window units. In addition, in certainexample embodiments, no titanium oxide based low deposition-ratematerial is used for high index layers in this design. Since thedeposition rate of ZrAlN for instance is much faster than those of Tibased high index oxides, and even faster than silicon nitride sputterdeposition rates, this design provides a benefit of increasedthroughput, and the deposition time on dielectric layers may be reducedby up to 40% so that the throughput is greatly benefitted.

Layers in the FIG. 1 sequence are important. Below the IR reflectinglayer, ZrAlN and ZrSiAlN provide for a high index material, fastdeposition rate, and low cost. Above the IR reflecting layer, withoutthe ZrAlN or ZrSiAlN, the overall performance desired is not achievedbecause of the high index feature provided by this material(s).Moreover, zinc oxide inclusive layer 7 (or 7′) is important, because ifZrAlN or ZrSiAlN is directly deposited to contact the contact layer 6(or 6′) of material such as NiTiNb or an oxide thereof, poortransmission has been found to result. In addition, such design showedexcellent queue time of low-E stack, where queue time is the coatingbeing exposed to ambient condition (after sputter depositing thecoating) until the film is subject to optional HT such as thermaltempering. In particular, the haze value does not significantly changeduring this time and remains at low levels such as about 0.2 or less.

FIG. 2 is a cross sectional view of a coated article according to anexample embodiment of this invention including two of the layersequences shown in FIG. 1 in a double silver low-E coating. The coatedarticle of FIG. 2 includes glass substrate S (e.g., clear, green,bronze, or blue-green glass substrate from about 1.0 to 10.0 mm thick,more preferably from about 1.0 mm to 6.0 mm thick), and a multi-layercoating (or layer system) provided on the substrate S either directly orindirectly. The example low-E coating according to the FIG. 2 embodimentmay include an optional medium index layer 1 of or including a materialsuch as silicon nitride (e.g., Si₃N₄) and/or silicon oxynitride, highindex transparent ZrSiN and/or ZrSiAlN dielectric layer 2, transparentdielectric layer 4 of or including zinc oxide which may be doped withfrom 1-10% Al (atomic %) and which may optionally include tin, IRreflecting layer 5 of or including silver, gold, or the like, contactlayer 6 of or including a material such as NiCr, NiCrO_(x), NiCrMoO_(x),NiCrMo, or NiTiNbO_(x), transparent dielectric layer 7 of or includingzinc oxide which may be doped with from 1-10% Al (atomic %) and whichmay optionally include tin, another high index transparent ZrSiN and/orZrSiAlN dielectric layer 2′, transparent dielectric layer 4′ of orincluding zinc oxide which may be doped with from 1-10% Al (atomic %)and which may optionally include tin, another IR reflecting layer 5′ ofor including silver, gold, or the like, another contact layer 6′ of orincluding a material such as NiCr, NiCrO_(x), NiCrMoO_(x), NiCrMo, orNiTiNbO_(x), another transparent dielectric layer 7′ of or includingzinc oxide which may be doped with from 1-10% Al (atomic %) and whichmay optionally include tin, yet another high index transparent ZrSiNand/or ZrSiAlN dielectric layer 2″, optional medium index layer 9 of orincluding material such as silicon nitride, silicon oxynitride, or zincoxide, and overcoat 10 of or including material such as silicon nitride,silicon oxynitride, or silicon oxide. The silicon nitride layers 1, 9may further include Al, oxygen, or the like, and the zinc oxide basedlayers 4, 4′, 7, 7′ may also include tin and/or aluminum. Other layersand/or materials may also be provided in the coating in certain exampleembodiments of this invention, and it is also possible that certainlayers may be removed or split in certain example instances. Moreover,one or more of the layers discussed above may be doped with othermaterials in certain example embodiments of this invention. Thisinvention is not limited to the layer stack shown in FIG. 2, as the FIG.2 stack is provided for purposes of example only in order to illustratean example location(s) for the layer sequence shown in FIG. 1.

In monolithic instances, the coated article includes only one substratesuch as glass substrate S (see FIGS. 1 and 2). However, monolithiccoated articles herein may be used in devices such as IG window unitsfor example. Typically, an IG window unit may include two or more spacedapart substrates with an air gap defined therebetween. Example IG windowunits are illustrated and described, for example, in U.S. Pat. Nos.5,770,321, 5,800,933, 6,524,714, 6,541,084 and US 2003/0150711, thedisclosures of which are all hereby incorporated herein by reference.For example, the coated glass substrate shown in FIG. 1 or FIG. 2 may becoupled to another glass substrate via spacer(s), sealant(s) or the likewith a gap being defined therebetween in an IG window unit. In certainexample instances, the coating may be provided on the side of the glasssubstrate S facing the gap, i.e., surface #2 or surface #3. In otherexample embodiments, the IG window unit may include additional glasssheets (e.g., the IG unit may include three spaced apart glass sheetsinstead of two).

Transparent dielectric zinc oxide inclusive layers 4, 4′, 7, 7′ may beof or include zinc oxide (e.g., ZnO), zinc stannate, or other suitablematerial. The zinc oxide may contain other materials as well such as Al(e.g., to form ZnAlOx) or Sn in certain example embodiments. Forexample, in certain example embodiments of this invention, any of theselayers may be doped with from about 1 to 10% Al (or B), more preferablyfrom about 1 to 5% Al (or B), and most preferably about 2 to 4% Al (orB).

Infrared (IR) reflecting layers 5, 5′ are preferably substantially orentirely metallic and/or conductive, and may comprise or consistessentially of silver (Ag), gold, or any other suitable IR reflectingmaterial. The silver of IR reflecting layers 5, 5′ may be doped withother material(s), such as with Pd, Zn, or Cu, in certain exampleembodiments. IR reflecting layers 5, 5′ helps allow the coating to havelow-E and/or good solar control characteristics such as low emittance,low sheet resistance, and so forth. The IR reflecting layers may,however, be slightly oxidized in certain embodiments of this invention.

Contact layers 6, 6′ are located over and directly contacting the IRreflecting layers, and may be of or include an oxide of Ni and/or Cr incertain example embodiments. In certain example embodiments, contactlayers 6, 6′ may be of or include nickel (Ni) oxide, chromium/chrome(Cr) oxide, or a nickel alloy oxide such as nickel chrome oxide(NiCrOx), or other suitable material(s) such as NiCrMoO_(x), NiCrMo, Ti,NiTiNbO_(x), TiO_(x), metallic NiCr, or the like. Contact layers 6, 6′may or may not be oxidation graded in different embodiments of thisinvention.

Oxidation grading means that the degree of oxidation in the layerchanges through the thickness of the layer so that for example a contactlayer may be graded so as to be less oxidized at the contact interfacewith the immediately adjacent IR reflecting layer than at a portion ofthe contact layer further or more/most distant from the immediatelyadjacent IR reflecting layer. Contact layers 6, 6′ may or may not becontinuous in different embodiments of this invention across the entireIR reflecting layer 4.

Other layer(s) below or above the illustrated FIG. 2 coating may also beprovided. Thus, while the layer system or coating is “on” or “supportedby” substrate S (directly or indirectly), other layer(s) may be providedtherebetween. Thus, for example, the coating of FIG. 2 may be considered“on” and “supported by” the substrate S even if other layer(s) areprovided between layer 1 and substrate S. Moreover, certain layers ofthe illustrated coating may be removed in certain embodiments, whileothers may be added between the various layers or the various layer(s)may be split with other layer(s) added between the split sections inother embodiments of this invention without departing from the overallspirit of certain embodiments of this invention.

While various thicknesses may be used in different embodiments of thisinvention, example thicknesses and materials for the respective layerson the glass substrate S in the FIG. 2 embodiment may be as follows,from the glass substrate outwardly (e.g., the Al content in the zincoxide and silicon nitride layers may be from about 1-10%, morepreferably from about 1-5% in certain example instances). Thickness arein units of angstroms (A).

TABLE 1 (Example Materials/Thicknesses; FIG. 2 Embodiment) More LayerPreferred Range (Å) Preferred (Å) Example (Å) Glass SubstrateSi_(x)N_(y (layer 1)) 40-300 Å 50-170 Å 70-130 Å ZrAlN or ZrSiAlN 50-500Å 60-350 Å 80-300 Å (layer 2) ZnAlO (layer 4) 30-250 Å 40-180 Å 40-100 ÅAg (layer 5) 40-160 Å 65-125 Å 110 Å Contact (layer 6)  10-70 Å 20-45 Å25-35 Å ZnAlO (layer 7) 30-250 Å 40-180 Å 40-100 Å ZrAlN or ZrSiAlN50-500 Å 60-350 Å 80-300 Å (layer 2′) ZnAlO (layer 4′) 30-250 Å 40-180 Å40-100 Å Ag (layer 5′) 40-160 Å 65-125 Å 110 Å Contact (layer 6′)  10-70Å 20-45 Å 25-35 Å ZnAlO (layer 7′) 30-250 Å 40-180 Å 40-100 Å ZrAlN orZrSiAlN 50-500 Å 60-350 Å 80-300 Å (layer 2″) Si_(x)N_(y) (layer 9)50-400 Å 100-300 Å 140-240 Å SiO₂ (layer 10) 50-600 Å 100-500 Å 200-400Å

In certain example embodiments of this invention, coated articles herein(e.g., see FIG. 2) may have the following low-E (low emissivity), solarand/or optical characteristics set forth in Table 2 when measuredmonolithically.

TABLE 2 Low-E/Solar Characteristics (Monolithic) More CharacteristicGeneral Preferred Most Preferred R_(s) (ohms/sq.): <=11.0 <=10 <=9E_(n): <=0.2 <=0.15 <=0.10 T_(vis) (%): >=50 >=60 >=70 (or >=80%) SHGC(%): >=40 >=50 >=55

In an example embodiment of this invention, there is provided a coatedarticle including a coating supported by a glass substrate, the coatingcomprising: a first high index dielectric layer comprising a nitride ofZr and Al on the glass substrate, wherein the first high indexdielectric layer comprising the nitride of Zr and Al contains more Zrthan Al; a first dielectric layer comprising zinc oxide on the glasssubstrate located over and directly contacting the first high indexlayer comprising the nitride of Zr and Al; a first infrared (IR)reflecting layer on the glass substrate, located over and directlycontacting the first dielectric layer comprising zinc oxide; a firstcontact layer on the glass substrate located over and directlycontacting the first IR reflecting layer; a second dielectric layercomprising zinc oxide on the glass substrate located over and directlycontacting the first contact layer; a second high index dielectric layercomprising a nitride of Zr and Al on the glass substrate located overand directly contacting the second dielectric layer comprising zincoxide, wherein the second high index dielectric layer comprising thenitride of Zr and Al contains more Zr than Al; and another dielectriclayer on the glass substrate located over at least the first and secondhigh index dielectric layers and the first IR reflecting layer.

In the coated article of the immediately preceding paragraph, each ofthe first and second high index dielectric layers may have a refractiveindex (n) of at least 2.21 at 550 nm, more preferably of at least 2.25at 550 nm.

In the coated article of any of the preceding two paragraphs, at leastone of the first and second high index dielectric layers may furthercomprise Si.

In the coated article of any of the preceding three paragraphs, metalcontent of each of the first and second high index dielectric layers maycomprise from 30-80% Zr and from 10-60% Al, more preferably from 35-75%Zr and from 15-50% Al, and most preferably from 55-70% Zr and from20-40% Al (atomic %).

In the coated article of any of the preceding four paragraphs, metalcontent of at least one of the first and second high index dielectriclayers may comprise from 3-25% Si, more preferably from 3-15% Si (atomic%).

In the coated article of any of the preceding five paragraphs, metalcontent of each of the first and second high index dielectric layers maycomprise at least twice as much Zr as Si, more preferably at least threeor four times as much Zr as Si.

In the coated article of any of the preceding six paragraphs, metalcontent of each of the first and second high index dielectric layers maycomprise at least 1.2 times as much Zr as Al, more preferably at least1.4 times as much Zr as Al.

In the coated article of any of the preceding seven paragraphs, thecoating may be a low-E coating having a normal emissivity (E_(n)) of nogreater than 0.2, more preferably of no greater than 0.10.

In the coated article of any of the preceding eight paragraphs, each ofthe first and second high index dielectric layers may be amorphous orsubstantially amorphous.

In the coated article of any of the preceding nine paragraphs, the firstIR reflecting layer may comprises silver, and an optional second IRreflecting layer may also comprise silver.

In the coated article of any of the preceding ten paragraphs, thecoating may further comprise a layer comprising silicon nitride locatedbetween the glass substrate and the first high index dielectric layer.

In the coated article of any of the preceding eleven paragraphs, thecoated article may be thermally tempered.

In the coated article of any of the preceding twelve paragraphs, thecoated article may have a visible transmission of at least 50%, morepreferably of at least 60%, even more preferably of at least 70%, andeven more preferably of at least 80%.

In the coated article of any of the preceding thirteen paragraphs, thefirst contact layer may comprises Ni and Cr.

In the coated article of any of the preceding fourteen paragraphs, thecoating may further comprise: a third dielectric layer comprising zincoxide on the glass substrate located over at least the a second highindex dielectric layer comprising a nitride of Zr and Al; a secondinfrared (IR) reflecting layer on the glass substrate, located over anddirectly contacting the third dielectric layer comprising zinc oxide; asecond contact layer on the glass substrate located over and directlycontacting the second IR reflecting layer; a fourth dielectric layercomprising zinc oxide on the glass substrate located over and directlycontacting the second contact layer; a third high index dielectric layercomprising a nitride of Zr and Al on the glass substrate located overand directly contacting the fourth dielectric layer comprising zincoxide, wherein the third high index dielectric layer comprising thenitride of Zr and Al contains more Zr than Al; and wherein said anotherdielectric layer is located over at least the third high indexdielectric layer.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

1-22. (canceled)
 23. A coated article including a coating supported by aglass substrate, the coating comprising: a first high index dielectriclayer comprising a nitride of Zr, Al and Si on the glass substrate,wherein the first high index dielectric layer contains more Zr than Al;a first dielectric layer comprising zinc oxide on the glass substratelocated over and directly contacting the first high index layercomprising the nitride of Zr, Al and Si; a first infrared (IR)reflecting layer on the glass substrate, located over and directlycontacting the first dielectric layer comprising zinc oxide; a firstcontact layer on the glass substrate located over and directlycontacting the first IR reflecting layer.
 24. The coated article ofclaim 23, wherein the first high index dielectric layer has a refractiveindex (n) of at least 2.21 at 550 nm.
 25. The coated article of claim23, wherein metal content of the first high index dielectric layercomprises from 30-80% Zr and from 10-60% Al (atomic %).
 26. The coatedarticle of claim 23, wherein metal content of the first high indexdielectric layer comprises from 35-75% Zr and from 15-50% Al (atomic %).27. The coated article of claim 23, wherein metal content of the firsthigh index dielectric layer comprises from 3-25% Si (atomic %).
 28. Thecoated article of claim 23, wherein the first high index layer is indirect contact with the glass substrate.